Booster actuator

ABSTRACT

A booster actuator  10  may be positioned between the solenoid  12  and a valve  14 , and increases the energy output from the solenoid to activate the valve. The booster actuator  10  may include a force input member  28  and a force output member  30  each linearly movable with respect to a body  20  from an initial position to an activated position. A coil spring  46  biases the input member to the initial input position, while a plurality of disk springs  48  bias the output member  30  to the activated output position. A plurality of linking members  32  each pivotable with respect to the body normally retain the force output member in the initial position, but upon movement of the input member to the activated position release the force output member in response to the disk springs.

FIELD OF THE INVENTION

The present invention relates to devices intended to be actuated by alow energy input, and which output a high energy to the device to beactuated. More particularly, the present invention relates to a boosteractuator which uses mechanically stored energy to move an actuator shaftwith a force and stroke sufficient to actuate various types of devices.

BACKGROUND OF THE INVENTION

Those involved in system designs have long required devices whichprovide a boost or energy level increase to actuate a device. Electricenergy input to a solenoid is directly proportional to the output force,which practically limits the use of solenoids in conventional low powerelectrical systems. A relatively small and inexpensive electricalsolenoid may send a signal which will stroke a solenoid plunger,although the force and/or the stroke of the plunger in many cases isinsufficient to activate the device intended. Accordingly, boosters havebeen used between such low energy products, such as solenoids, and adevice to be activated to provide the desired energy level to actuatethe intended device.

In the fire safety industry, various systems have been devised so thatpressurized gas maybe released when a device is manually orautomatically actuated. In some applications, a booster or boosteractuator may be positioned between a solenoid and a valve, with thatvalve in turn being actuated to release agents, such as CO₂ or a mixtureof nitrogen, argon, and carbon dioxide, into the hazard area.

Prior art booster actuators have used magnetized components to hold theactuator in the set or armed position. Many of these actuators requirean input force proportional to the desired output force, or requireadditional electrical circuitry to return the actuator to the setposition.

Prior art actuators also include pressurized gas cartridges which arepunctured, so that the release of the pressurized gas in response to thepuncture may be used to activate a pneumatic device which releases theagent gas to the hazard area. Other types of actuators utilize explosivecomponents to generate the increased energy to activate a valve orotherwise release the agent gas to the hazard area.

Many prior art boost devices have significant disadvantages which havelimited their use. Prior art boost devices are relatively complex and/orare not highly reliable, and other devices cannot be easily reset. Instill other booster devices, it is difficult to vary the force whichactivates the boost device and/or to vary the output force from theboost device. The disadvantages of the prior art are overcome by thepresent invention, and an improved booster actuator is hereinafterdisclosed.

SUMMARY OF THE INVENTION

In a typical application, the booster actuator of the present inventionmay be located between a solenoid and a valve. The actuator body housesa cam shaft or force input member which is biased by a coil spring tothe initial input position. The body also houses an actuator shaft orforce output member which is biased to the activated output position bya plurality of disk springs. A plurality of circumferentially spacedlinks engage the force input member at one end and the force outputmember at the other end, and control of the release of the force fromthe disk springs to the output member in response to movement of the camshaft. In another embodiment, an electrical coil is provided about thecam shaft, so that a combination solenoid and booster is provided.

It is an object of the present invention to provide a booster apparatuswith a force input member and a force output member each movablerelative to the actuator body, a biasing member for biasing the forceoutput member to the activated output position and at least one linkingmember between the force input member and the force output member andpivotably movable with respect to the body from the engaged position toa disengaged position for releasing the force output member to theactivated output position in response to the biasing member. The linkingmember engages both the force input member and force output member, andmay cooperate with recesses in the input member and output member forachieving the desired function.

It is another feature of the invention to provide a booster actuatorwith a force input member, a low force biasing member for exerting abiasing force on the input member, a force output member, anotherbiasing member for exerting a high biasing force on the force outputmember, and a linking member between the force input member and forceoutput member. Control of the actuator may be reliably obtained byproviding two biasing members each of which exert a force independent ofthe other biasing member on the input member or output member.

It is a feature of the present invention to provide a booster actuatorwherein the output force from the actuator may be easily revised withoutredesigning the remainder of the actuator. Moreover, the change in theoutput force is independent of the energy required to trigger activationof the booster, and the input energy required to trigger the actuatormay be separately selected without regard to the output requirementsfrom the actuator.

It is another feature of the invention that the booster actuator ishighly reliable, and may be mechanically reset without the use ofelectrical devices. The reset may be accomplished quickly and easily,and no replacement of parts is necessary.

It is a further feature of the invention to provide a booster actuatorwherein a solenoid coil is provided to control movement of the forceinput member relative to the actuator body.

It is an advantage of the present invention that the booster apparatusis highly reliable and may be economically manufactured. The boosterbody preferably seals the internal components from the environment.

These and further objects, features, and advantages of the presentinvention will become apparent from the following detailed description,wherein reference is made to the figures in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified cross-sectional view of a booster actuatoraccording to the present invention positioned between an electricallyactivated solenoid and a valve which is connected to a pressurized gassystem.

FIG. 2 is a cross-sectional view of a booster actuator generally shownin FIG. 1. An internal portion of the body has been removed for clarityof the illustrated components.

FIG. 3 is a cross-sectional view of the body generally shown in FIG. 2.

FIG. 4 is another cross-sectional view of the body, illustrating thespaced apart guides for receiving each of the four linking members.

FIG. 5 is a side view of a suitable booster reset device.

FIG. 6 is a side view of a portion of an alternate embodiment, with anelectrical coil surrounding the cam shaft.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, the booster actuator 10 may be threadedly securedat one end to the body of a solenoid 12 or another electrically actuateddevice, and may be similarly connected at its opposed end to a valve 14,with the valve 14 intended to release gas to an area in response to asensed hazardous condition. The booster apparatus thus may be used inconjunction with a relatively low energy electrical system whichmonitors the surrounding environment, and outputs an electrical signalto actuate the solenoid 12 in response to the sensed condition torelease a selected gas, e.g., for extinguishing a fire. As shown in FIG.1, the solenoid 12 includes a plunger 13 which is movable relative tothe body 20 of the booster actuator 10. The actuator 10 receives thislow energy input and outputs a high energy to control plunger 15 of thevalve 14, thereby activating the valve 14 to release the compressed gasto the environment.

The actuator 10 as shown in FIG. 2 includes a body 20 having a forcereceiving input end 22 and a force delivery output end 24. Outer sleeve25 may be provided for engagement with conventional seals 26 to seal theinterior of the body. The cam shaft or force input member 28 is movablerelative to the body from an initial input position as shown in FIG. 2to an activated output position in response to movement of the solenoidplunger. The force output member 30 is similarly movable relative to thebody from the initial output position as shown in FIG. 2 to an activatedoutput position. Four links 32 are equally spaced at 90° intervals aboutboth the force input member and the force output member, and are eachpivotable about the pin 34 which is supported on the body 20. The coilspring 46 biases the force input member to the initial input position,and a plurality of disk springs, such as disk springs 48, bias theoutput member 30 to the activated output position.

The force input member 28 is sealed with the body by a conventionalO-ring 50, and in the initial input position is biased by the coilspring 46 to engage shoulder 52 on the body. Input member 28 includes anannular recess 54 for receiving the upper end of each of the linkingmembers 32 when in the disengaged position, thereby allowing release ofthe force output member 30 normally held in the initial position by thelower end of each linking member. As indicated in FIG. 2, an upperroller 56 may be provided at the upper end of each link 32, and asimilar roller 58 may be provided at the lower end of each link. Whenthe actuator is in the initial position, each of the upper rollers thusengages the cylindrical exterior surface 64 of the input member 28,while each lower roller 58 fits at least partially within annular recess66 in the force output member 30. Each roller is rotatably mounted on alink with a respective pin 60 which is fixed to the link, and each linkitself is pivotable about pin 34 which is supported on the actuator body20. The position of the input member 28 thus retains each of the fourlinks in the position as shown in FIG. 2, which in turn preventsdownward movement of the force output member 30 in response to the disksprings 48.

A stop plate 62 has a central aperture therein sized to receive plunger68 of the force output device 30, with the stop plate beinginterconnected with the body by threads 70. Conventional ports 72 may beprovided in the stop plate for receiving a suitable tool to thread thestop plate in place, with the final position of the stop plate restingagainst snap ring 74. An O-ring 76 is held in position within the stopplate by a combination back-up ring and retaining ring 78, and providessealing engagement between the plunger 68 and the stop plate 62.

It is a particular feature of the invention that the force required tomove the input member 28 may be easily adjusted by varying the selectionof the coil spring 46. The coil spring is sized so that the boosteractuator will not inadvertently activate in response to vibration,jarring, and other forces commonly transmitted to a system. Theselection of the number of coils and the material for the coils for thespring 46 are independent, however, of the selection of the biasingmember 48, which preferably is a plurality of disk springs. The numberof disk springs and the orientation of these springs with respect toeach other affect the force and the stroke which will move the forceoutput member to the activated position, thereby extending the plungerfrom the stop plate and, in an exemplary application, actuating thevalve as shown in FIG. 1. For this exemplary embodiment, it should beunderstood that the force output member may move from the initialposition as shown in FIG. 2 to a position wherein the surface 81 engagesthe snap ring 74. This movement of the force output member 30 to theactivated output position thus results when each of the rollers 58 movesout of engagement with the recess 66, so that each of the rollers 58rolls out of the recess and into engagement with the cylindrical surface67 on force output member 30. At the same time, upper rollers 56 rollout of engagement with the cylindrical surface 64 in the force inputmember and roll partially at least within the annular recess 54 sized toreceive these rollers. This action thus causes pivoting of the links 32to release the force output member to the activated position.

FIG. 3 shows in greater detail the construction of a suitable actuatorbody 20, and particularly the cavity 80 for receiving the disk springs48. The uppermost disk spring as shown in FIG. 2 thus rests against thesurface 82 as shown in FIG. 3. FIGS. 3 and 4 also depict four pairs ofcircumferentially spaced guide plates 86 and 88, thereby providing aslot 90 therebetween for receiving a suitable link 32. FIG. 4 alsodepicts the aligned throughports 92 in each pair of guide plates forreceiving a suitable link pin 34. The lower flange 94 of the body 20 mayhave a suitable exterior configuration, such as a hex configuration, forengagement with a conventional tool to facilitate threadably connectingthe body 20 to a solenoid.

It is a feature of the invention that the interior of the body 20 andthus each of the movable components within the body is sealed from thesurrounding environment, with this objective being accomplished by theconventional seals 26 which seal between sleeve 25 and the body, and bythe seals 50 and 76 which seal with the force input member and the forceoutput member, respectively. A sufficient seal may be created betweenthe body 20 and the stop plate 62 due to interference of the threadsalthough, if desired, another O-ring seal could be provided for sealingbetween the stop plate and the body.

In preferred embodiments, at least three linking members arecircumferentially arranged about the force input member and the forceoutput member. Three linking members at 120° interval spacing providehigh reliability by distributing the applied forces equally about theinput member and the output member. A preferred embodiment as shown inthe figures utilizes four linking members spaced at 90° intervals. Therollers 56 and 58 provided at the end of the linking members reducefrictional forces when the linking members are moved from an engagedposition as shown in FIG. 2 for retaining the force output member 30 inthe initial output position to a disengaged position which releases theforce output member to the activated output position. In alternateembodiments, the rollers may be eliminated, or may be replaced withother conventional members intended to reduce friction with the forceinput and force output members.

Coil spring 46 acts between the force output member 30 and the forceinput member 28. The force of this spring may be easily altered withoutmodifying other components of the booster actuator in order to changethe force required to activate the booster 10. Similarly, the size,orientation, and number of disk springs 48 may be altered to effect thestroke length and/or the force which will be output by the plunger 68when moved to the activated output position. Alternative types ofsprings or other biasing members may be utilized.

The booster actuator of the present invention provides a mechanicalseparation of the input member and the output member. The coil spring 46biases the input member to the initial position, but this exerts a smallforce on the output member compared to the bias of the springs 48. Byproviding no direct mechanical connection between the input member andthe output member, the reactive forces on the valve which aretransmitted back to the force output member during actuation of thebooster are prevented from being transmitted to the force input memberand then to the solenoid. The coil spring thus isolates the reactiveforce on the output member from the forces applied to the input member,and a latching solenoid mechanism may thus be used to activate thebooster without fear of damage from these reactive forces.

Once the booster is activated, the booster may be easily reset withoutuse of electrical devices, and without replacement of parts. After thevalve 14 has been removed from the booster body, reset device 94 asshown in FIG. 5 may be connected to the threads 70 on the body. Afterthe reset outer body 96 bottoms out against the stop plate 62, the bolt98 may be rotated relative to outer body 96 to project the tip 97 towardthe stop plate 62. The tip 97 is thereby forced into engagement with theend of the plunger 68, thereby forcing the force output member 30 backto the initial position as shown in FIG. 2. The return of the forceoutput member to the initial position also increases the force on thecoil spring to return the force input member to the initial position.

FIG. 6 depicts another embodiment of the invention, wherein acombination solenoid and booster actuator is provided. That portion ofthe booster 10 to the right of the force input member 128 may be asdescribed above. In this embodiment, however, an extension of the forceinput member is provided so that the extended length force input member128 is positioned within a solenoid coil 114. The solenoid coil may alsobe referred to as a magnetic latch subassembly, which receiveselectrical power to selectively move the input member 128. Those skilledin the art will appreciate that an extended length force input membermay be used, as shown, or a two-piece or multi-piece mechanicalinterconnection made between the solenoid plunger and the force inputmember. Activation of the coil 114 thus initiates movement of thesolenoid plunger, which in this case is the force input member 128.Force input member 128 includes a stop 130 for engagement with thesurface 132 to limit the travel of the force input member. FIG. 6depicts sleeve 134 enclosing the solenoid 114, and body 136 whichconnects sleeve 134 with sleeve 25.

While a preferred embodiment of the present invention has beenillustrated in detail, it is apparent that modifications and adaptationsof the proposed embodiment will occur to those skilled in the art.However, it is to be expressly understood that such modifications andadaptations are within the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A booster actuator for receiving a low energyinput and outputting a high energy output to operate a device, thebooster comprising: a body having a force receiving input end and forcedelivery output end; a force input member movable relative to the bodyin direct response to the low energy input from an initial inputposition to an activated input position; a force output member movablerelative to the body in response to movement of the force input memberfrom an initial output position to an activated output position, theforce output member being independently movable with respect to theforce input member; a biasing member for biasing the force output memberto the activated output position; and a linking member between the forceinput member and the force output member and pivotally movable withrespect to the body from an engaged position for retaining the forceoutput member in the initial output position to a disengaged positionfor releasing the force output member to the activated output position,the linking member having an input end engaging the force input memberand an output end engaging the force output member.
 2. The boosteractuator as defined in claim 1, further comprising: another biasingmember for biasing the force input member to the initial input position.3. The booster actuator as defined in claim 1, wherein the force outputmember includes an output member recess for receiving a lower end of thelinking member when in the engaged position.
 4. The booster actuator asdefined in claim 3, wherein the force input member includes an inputmember recess for receiving an upper end of the linking member when inthe disengaged position, thereby allowing disengagement of the lower endof the linking member from the output member recess.
 5. The boosteractuator as defined in claim 1, wherein at least three linking memberseach pivotable with respect to the body are circumferentially arrangedabout the force input member and the force output member.
 6. The boosteractuator as defined in claim 5, wherein four linking members are spacedcircumferentially at approximately 90° intervals about the force inputmember and force output member.
 7. The booster actuator as defined inclaim 1, further comprising: the biasing member comprises a plurality ofdisk springs; and another biasing member for biasing the force inputmember to the initial input position.
 8. The booster actuator as definedin claim 1, wherein each of the input end and output end of the linkingmember is provided with a roller for engaging the force input member andthe force output member, respectively.
 9. The booster actuator asdefined in claim 1, wherein the force delivery output end of the bodyincludes threads, and a reset member threaded to the delivery output endis rotated relative to the body to forceably engage the force outputmember to move the force output member from the activated position tothe initial position.
 10. A booster actuator as defined in claim 1,wherein the low energy input is a primary motive force acting on theforce input member to move to the activated input position.
 11. Abooster actuator as defined in claim 1, further comprising: a pluralityof linking members each between the force input member and the forceoutput member and pivotally movable relative to the body from an engagedposition for retaining the force output member in the initial outputposition to a disengaged position for releasing the force output memberto the activated output position, the linking members beingcircumferentially arranged about the force input member and the forceoutput member and each having an input end engaging the force inputmember and an output end engaging the force output member.
 12. A boosteractuator as defined in claim 1, further comprising: the force outputmember includes an output member recess for receiving a lower end ofeach of the linking members when in the engaged position.
 13. A boosteractuator as defined in claim 1, further comprising: a first biasingmember for biasing the force output member to the activated outputposition; a second biasing member for biasing the output force member tothe activated output position.
 14. A booster actuator for receiving alow energy input and outputting a high energy output to operate anotherdevice, the booster comprising: a body having a force receiving inputend and force delivery output end; a force input member linearly movablerelative to the body in direct response to the low energy input from aninitial input position to an activated input position; a first biasingmember for biasing the force input member to the initial input position;a force output member linearly movable relative to the body in responseto movement of the force input member from an initial output position toan activated output position, the force output member beingindependently movable with respect to the force input member; a secondbiasing member for biasing the force output member to the activatedoutput position; and a linking member between the force input member andthe force output member and movable from an engaged position forretaining the force output member in the initial output position to adisengaged position for releasing the force output member to theactivated output position.
 15. The booster actuator as defined in claim14, wherein at least three linking members each pivotable with respectto the body are circumferentially arranged about the force input memberand the force output member.
 16. The booster actuator as defined inclaim 14, wherein the first biasing member is a coil spring, and thesecond biasing member comprises a plurality of disk springs.
 17. Thebooster actuator as defined in claim 14, wherein each of the input endand output end of the linking member is provided with a roller forengaging the force input member and force output member, respectively.18. A booster actuator as defined in claim 14, wherein the low energyinput is a primary motive force acting on the force input member to moveto the activated input position.
 19. A booster actuator as defined inclaim 14, further comprising: a plurality of linking members eachbetween the force input member and the force output member and pivotallymovable relative to the body from an engaged position for retaining theforce output member in the initial output position to a disengagedposition for releasing the force output member to the activated outputposition, the liking members being circumferentially arranged about theforce input member and the force output member and each having an inputend engaging the force input member and an output end engaging the forceoutput member.
 20. A booster actuator as defined in claim 14, furthercomprising: a first biasing member for biasing the force output memberto the activated output position; a second biasing member for biasingthe output force member to the activated output position.